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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: V4L
+
+.. _VIDIOC_ENUMOUTPUT:
+
+***********************
+ioctl VIDIOC_ENUMOUTPUT
+***********************
+
+Name
+====
+
+VIDIOC_ENUMOUTPUT - Enumerate video outputs
+
+Synopsis
+========
+
+.. c:macro:: VIDIOC_ENUMOUTPUT
+
+``int ioctl(int fd, VIDIOC_ENUMOUTPUT, struct v4l2_output *argp)``
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :c:func:`open()`.
+
+``argp``
+ Pointer to struct :c:type:`v4l2_output`.
+
+Description
+===========
+
+To query the attributes of a video outputs applications initialize the
+``index`` field of struct :c:type:`v4l2_output` and call
+the :ref:`VIDIOC_ENUMOUTPUT` with a pointer to this structure.
+Drivers fill the rest of the structure or return an ``EINVAL`` error code
+when the index is out of bounds. To enumerate all outputs applications
+shall begin at index zero, incrementing by one until the driver returns
+``EINVAL``.
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. c:type:: v4l2_output
+
+.. flat-table:: struct v4l2_output
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``index``
+ - Identifies the output, set by the application.
+ * - __u8
+ - ``name``\ [32]
+ - Name of the video output, a NUL-terminated ASCII string, for
+ example: "Vout". This information is intended for the user,
+ preferably the connector label on the device itself.
+ * - __u32
+ - ``type``
+ - Type of the output, see :ref:`output-type`.
+ * - __u32
+ - ``audioset``
+ - Drivers can enumerate up to 32 video and audio outputs. This field
+ shows which audio outputs were selectable as the current output if
+ this was the currently selected video output. It is a bit mask.
+ The LSB corresponds to audio output 0, the MSB to output 31. Any
+ number of bits can be set, or none.
+
+ When the driver does not enumerate audio outputs no bits must be
+ set. Applications shall not interpret this as lack of audio
+ support. Drivers may automatically select audio outputs without
+ enumerating them.
+
+ For details on audio outputs and how to select the current output
+ see :ref:`audio`.
+ * - __u32
+ - ``modulator``
+ - Output devices can have zero or more RF modulators. When the
+ ``type`` is ``V4L2_OUTPUT_TYPE_MODULATOR`` this is an RF connector
+ and this field identifies the modulator. It corresponds to struct
+ :c:type:`v4l2_modulator` field ``index``. For
+ details on modulators see :ref:`tuner`.
+ * - :ref:`v4l2_std_id <v4l2-std-id>`
+ - ``std``
+ - Every video output supports one or more different video standards.
+ This field is a set of all supported standards. For details on
+ video standards and how to switch see :ref:`standard`.
+ * - __u32
+ - ``capabilities``
+ - This field provides capabilities for the output. See
+ :ref:`output-capabilities` for flags.
+ * - __u32
+ - ``reserved``\ [3]
+ - Reserved for future extensions. Drivers must set the array to
+ zero.
+
+
+.. tabularcolumns:: |p{7.0cm}|p{1.8cm}|p{8.7cm}|
+
+.. _output-type:
+
+.. flat-table:: Output Type
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 3 1 4
+
+ * - ``V4L2_OUTPUT_TYPE_MODULATOR``
+ - 1
+ - This output is an analog TV modulator.
+ * - ``V4L2_OUTPUT_TYPE_ANALOG``
+ - 2
+ - Any non-modulator video output, for example Composite Video,
+ S-Video, HDMI. The naming as ``_TYPE_ANALOG`` is historical,
+ today we would have called it ``_TYPE_VIDEO``.
+ * - ``V4L2_OUTPUT_TYPE_ANALOGVGAOVERLAY``
+ - 3
+ - The video output will be copied to a :ref:`video overlay <overlay>`.
+
+
+.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+
+.. _output-capabilities:
+
+.. flat-table:: Output capabilities
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 3 1 4
+
+ * - ``V4L2_OUT_CAP_DV_TIMINGS``
+ - 0x00000002
+ - This output supports setting video timings by using
+ ``VIDIOC_S_DV_TIMINGS``.
+ * - ``V4L2_OUT_CAP_STD``
+ - 0x00000004
+ - This output supports setting the TV standard by using
+ ``VIDIOC_S_STD``.
+ * - ``V4L2_OUT_CAP_NATIVE_SIZE``
+ - 0x00000008
+ - This output supports setting the native size using the
+ ``V4L2_SEL_TGT_NATIVE_SIZE`` selection target, see
+ :ref:`v4l2-selections-common`.
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EINVAL
+ The struct :c:type:`v4l2_output` ``index`` is out of
+ bounds.